I had a problem the other day where my network connection went into a blocking state.  (This has now happened twice when I had wireguard configured, but I've not yet assigned blame - different story).

 

Luckily I was home when it happened overnight and so I could just go in and reboot manually via the gui in the server room.  But what would happen if this happens and I'm away on holiday?  The server does seem completely fine, except that I can't reach it via SSH or the WEB GUI.  Would a second NIC help to login via should the main enter blocking state?  Any ideas or suggestions?

This is where server grade hardware shines. IPMI or Idrac or whatever remote management solution built in to most server grade motherboards allows you to log in and at the very least power cycle the machine, most will allow some sort of console access so you can shut down properly.